The use of narcotic drugs to control severe, chronic pain is clearly the most common form of analgesic therapy in patients with cancer. Unfortunately, such treatment is associated with the problems of tolerance, physical and psychological dependence, nausea, vomiting, sedation, mental clouding and dysphoria. Recent reports from Great Britain and Canada have claimed that the addition of cocaine and a phenothiazine (known as brompton mixture) in a syrup elixir have achieved pain relief without any of those effects. Since there are no randomized clinical trials of such mixtures, it provides an opportunity to apply modern clinical pharmacologic methodology to the evaluation of a potentially useful therapy. The present study has two broad goals. (A) It is a cross-over design with random assignment which will: (1) compare the Brompton mixture (morphine, cocaine, alcohol plus phenothiazine) with oral morphine alone; (2) evaluate the effect of changing the amount of cocaine and of phenothiazines; (3) evaluate the effect of substitution of haloperidol for the phenothiazine. (B) It represents the development of a model for: (1) the evaluation of chronic analgesic therapy; (2) uses a series of sensitive psychological test instruments to assess mood cjanges in concert with pain relief; and (3) uses a computer based decision tree which allows the double-blind state to be maintained during the study. The results of these studies will form the basis for a more rational approach to the management of chronic pain and suggest ways to prevent the development of tolerance and dependence.